Contents lists available at ScienceDirect Journal of Affective Disorders journal homepage: www.elsevier.com/locate/jad Review article Temporal distribution of suicide mortality: A systematic review Pauliana Valéria Machado Galvão a, ⁎ , Hugo Rafael Souza e Silva b , Cosme Marcelo Furtado Passos da Silva a a Department of Epidemiology and Quantitative Methods in Health, Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz, Brazil b School of Medicine, Serra Talhada Campus, Universidade de Pernambuco, Brazil ABSTRACT Background: suicide is a problem with world impact and the leading cause of premature deaths. The study of its distribution over time can bring a changed understanding of parameters attributed to, and the prevention of, suicide. Aim: to identify the temporal pattern of suicide by systematic review. Methods: Pubmed (Medline), LILACS, Virtual Health Library (VHL), Science Direct and Scopus (Elsevier), Web of Science (Thomson Reuters) and PsyNET (APA) were searched, using suicide-related descriptors and terms, for observational epidemiological studies of the temporal distribution of suicide. The review protocol was registered in PROSPERO (CRD42016038470). Limitations: The lack of uniformity in reporting or standardisation of methodology in the studies selected, hindered comparison of populations with similar socioeconomic and cultural profiles, considerably limiting the scope of the results of this review. Results: forty-five studies from 26 different countries were included in this review. Clear seasonal patterns were observed by day of the week, month, season and age-period-cohort effects. Few studies studied by trend, time of day or day of the month. Conclusion: the review findings provide further evidence of substantial temporal patterns influenced by geo- graphic, climatic and social conditions. 1. Introduction Suicide is a complex public health problem and the leading cause of premature death (Mars et al., 2014; Turecki and Brent, 2016). It is also an event that belongs to one of those research domains where much is known, but not enough is understood (Ajdacic-Gross et al., 2003). The world impact is one death every 40 s or just over 800 000 deaths worldwide in 2012 representing an annual global age standardized suicide rate of 11.4 per 100 000, the second leading cause of death among 15–29 year olds, and 15th-most common cause of death worldwide (World Health Organization, 2014). This disorder produces such repercussions that the World Health Organization's Comprehen- sive Mental Health Action Plan sets a target of 10% reductions in countries’ annual rates by 2020 (World Health Organization, 2013). Suicidal behaviour is strongly associated with conflicts, disasters, violence, abuse, feelings of isolation (Turecki, 1999), feelings of hopelessness and helplessness, stress and distress (Kaplan et al., 2002; Parente et al., 2007; Sá et al., 2010), sleep disorders, including insomnia (Pompili et al., 2013), mood disorders, mental disorders (in- cluding schizophrenia, personality disorders, addiction), impulsivity, alcoholism or drug abuse, anorexia, anxiety and depression (Asirdizer et al., 2010; Pretti and Miotto, 1998). Many others factors may con- tribute to suicide, as economic problems, the loss of a loved one, con- flicts in the family, employment and problems at work, somatic illness, and honor (World Health Organization, 2002). In the past fifty years, suicide rates have increased significantly (60%) worldwide (Macente and Zandonade, 2011; Parente et al., 2007). These rates are unevenly distributed by country, sex, age group and method used (Minayo et al., 2012). Most suicides occur in low- and middle-income countries, where resources and services for early iden- tification, treatment and support of people in need are often scarce and limited, if indeed they exist (Saxena et al., 2014). In addition, suicide rates tend to be under-notified because of weak surveillance systems, misattribution of suicide as accidental death, as well as the crim- inalisation of suicide in some countries (World Health Organization, 2013). One of the fields that has most attracted researchers’ attention is https://doi.org/10.1016/j.jad.2017.12.008 Received 1 August 2017; Received in revised form 26 October 2017; Accepted 3 December 2017 ⁎ Correspondence to: Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz, Rua Leopoldo Bulhões, 1480 - sala 802, Manguinhos, 21041210 - Rio de Janeiro, RJ - Brazil. E-mail address: mscpauliana@hotmail.com.br (P.V.M. Galvão). Journal of Affective Disorders 228 (2018) 132–142 Available online 07 December 2017 0165-0327/ © 2017 Elsevier B.V. All rights reserved. T